FAR LATERAL LUMBAR DISC HERNIATION

Far lateral disc herniation is defined as a herniated disc located at or lateral to the pedicle. The incidence of these lesions has been reported to range between 2.6 and 11.7% of all lumbar disc herniations. 1 Far lateral disc herniations result in compression of the exiting nerve root rather than the traversing nerve root (i.e., a far lateral L3-4 disc herniation results in compression of the L3 nerve root) and there is a higher incidence of involvement of the upper lumbar segments. In a review of several series, L1-2 was the affected level in 0.3%, L2-3 in 5.4%, L3-4 in 25%, L4-5 in 52%, and L5-S1 in 17% of patients (Table 1). 1 In contradistinction, medially herniated disc fragments above the L4-5 level have an incidence of only 2.5%. 1 In one series of 170 patients with far lateral disc herniations, the average age of presentation was 55, and there were 112 men and 58 women in the study. 2